Question

A boy read 2/7 th of of the book in one day and 4/5 th of the remaining on another day. lf there were 12 pages unread. How many pages in the book​

Answer 1

Answer:

Remaining pages= 12. So, x/7=12. x= 12*7=84pages. The book contains 84 pages

Step-by-step explanation:

Answer 2

Answer:

• Total number of page in the books is 84 pages.

Step-by-step explanation:

Given that:

• A boy reads 2/7 of a books in one day and 4/5 of the remaining on another day.
• There were 12 pages left unread.

To Find:

• How many pages were in the book?

Let us assume:

• Let the total pages in the book be x.

Pages read on 1st day:

$\rm{\longmapsto\left(\dfrac{2}{7}\times x\right)}$

Multiplying,

$\rm{\longmapsto\dfrac{2x}{7}}$

Remaining pages:

$\rm{\longmapsto x-\dfrac{2x}{7}}$

Solving further,

$\rm{\longmapsto \dfrac{7x-2x}{7}}$

Subtracting,

$\rm{\longmapsto \dfrac{5x}{7}}$

Pages read on another day:

$\rm{\longmapsto\left(\dfrac{4}{5}\times\dfrac{5x}{7}\right)}$

Cutting off like terms,

$\rm{\longmapsto\left(\dfrac{4}{\!\not{5}}\times\dfrac{\!\not{5}x}{7}\right)}$

Multiplying,

$\rm{\longmapsto\dfrac{4x}{7}}$

According to the question:

$\rm{\longmapsto\dfrac{2x}{7}+\dfrac{4x}{7}+12=x}$

Transposing variables to LHS, constants to RHS and changing its sign,

$\rm{\longmapsto\dfrac{2x}{7}+\dfrac{4x}{7}-x=-12}$

Solving further

$\rm{\longmapsto\dfrac{2x+4x-7x}{7}=-12}$

$\rm{\longmapsto\dfrac{-x}{7}=-12}$

Transposing 7 from LHS to RHS and changing its sign,

$\rm{\longmapsto-x=-12\times7}$

Multiplying the numbers,

$\rm{\longmapsto-x=-84}$

$\rm{\longmapsto x=84}$

Hence,

• Value of x = 84.

Therefore,

• Total pages in the book is 84 pages.